It's important to trust your ears I think. I use a balanced isolation transformer that works very well, but a while back I tried a conventional RFI filter and it did horrible things to the sound. The article I linked to gives a plausible explanation of why this was the case. I wouldn't generalize that all such filters are bad in all situations, but clearly success isn't guaranteed with them.
I totally agree.
I'm relatively new at this but came to that conclusion a while ago. I suppose after the soldering iron and multimeter the next logical step, IF I'm to venture any further in this hobby, would be a scope.
Scopes are indispensable, as are your ears, and sometimes more trustworthy. You can find used Teks for less than $200 every day.
The discussion about power condition goes on forever. Some devices such as center tapped, balanced isolation trafos have meaningful value, especially in urban and industrial neighborhoods. A lot of the high priced conditioners are little more than a simple line filter in a fancy box. There have been several articles about building line conditioners and their function in AudioExpress over the years. They can ease the strain on your gear's PS, but ultimately the PS is where to spend the money. Snubbers have become very popular for this very reason.
The discussion about power condition goes on forever. Some devices such as center tapped, balanced isolation trafos have meaningful value, especially in urban and industrial neighborhoods. A lot of the high priced conditioners are little more than a simple line filter in a fancy box. There have been several articles about building line conditioners and their function in AudioExpress over the years. They can ease the strain on your gear's PS, but ultimately the PS is where to spend the money. Snubbers have become very popular for this very reason.
I completely agree! I don't believe in AC filters unless they are designed based on custom measurements. After all we are talking about a filter so in order to filter out something you need to know the load impendence.
Isolation trafos are more likely to do the job. This one had tremendous impact on the system of one of my audio-buddies, 5 stars to this:
SAC Thailand
Another very good device is this one from the Italian Cabre, they do wonderful stuffs even though they don't have a proper international marketing. I learned this company from an Italian friend. From what I know they focus on high-frequency electronics and audio is just a sort of part-time job. Anyway they do this:
:: CABRE Hi-Fi :.
Even though it filters out some mains noise, its primary goal is to suppress all the nasty things happening on the AC mains like micro-interruptions, cycles out of limits and stuffs like that. Moreover it guarantees that all components are are wired in phase. I noticed a big improvements on my DAC with this in the chain when the air conditions is on... I discovered that the air condition motor inject a lot of **** in my system!
Best
K
PCM1798 vs PCM1794
Last night Praudio and I did a listening session to compare the two Burr-Brown DACs. They show an obvious "family sound" but they don't have the same performances at all. The PCM1794 is more dynamic, transparent and "sizzling" than the 1798. In the counterpart, the last one is smoother. Let's remind the output transformers are the LL1674. The results would have not been probably that obvious with my previous UTC A20. The combo "PCM1798 + A20" was quite good over the "CS4398 + A20". So if you look for performances, the 1794 worth the few dollards more...
Last night Praudio and I did a listening session to compare the two Burr-Brown DACs. They show an obvious "family sound" but they don't have the same performances at all. The PCM1794 is more dynamic, transparent and "sizzling" than the 1798. In the counterpart, the last one is smoother. Let's remind the output transformers are the LL1674. The results would have not been probably that obvious with my previous UTC A20. The combo "PCM1798 + A20" was quite good over the "CS4398 + A20". So if you look for performances, the 1794 worth the few dollards more...
I should receive my PCM1798 board during this week. I will try it with UTC HA108 transformers in step up mode and with an outboard tube stage.
With the PCM board and the LL1674 Lundahls, did you load the dac with a resistor at the transformer primary to do I/V conversion or it is only loaded at the transformer secondary to get something near 100 ohms at the primary ?
Thanks
With the PCM board and the LL1674 Lundahls, did you load the dac with a resistor at the transformer primary to do I/V conversion or it is only loaded at the transformer secondary to get something near 100 ohms at the primary ?
Thanks
I read from the board compatible chips is cs4397/98, cs43122, pcm1793/98.....but there's no pcm1794????? Is 1794 100% compatible without any problem????? Tested here but I'm still worried.....!!!
Anyone can comment...?
Resistors at the primary like I did with the "1798-A20" combo. Tried also a load at the secondary (just take two resistors) like they do for the Rakk dac pasive output stage but I prefer the first way (better results in my set up). Anyway, you can "play" with different loads and tell us your findings
.Resistors at the primary like I did with the "1798-A20" combo. Tried also a load at the secondary (just take two resistors) like they do for the Rakk dac pasive output stage but I prefer the first way (better results in my set up). Anyway, you can "play" with different loads and tell us your findings
Kevin(K&K) suggested a 5K load for the PCM1798. What exactly is your setup please? I noticed in your pic you have jumper wires going from R+ R- L+ L- to pins 19/20/23/24. Besides removing opamps from under the board and parts on top(as shown in pic) is there anything else that needs to be done?
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I read from the board compatible chips is cs4397/98, cs43122, pcm1793/98.....but there's no pcm1794????? Is 1794 100% compatible without any problem????? Tested here but I'm still worried.....!!!
Anyone can comment...?
PCM1794 is 100% pin compatible with PCM1794
And I know the MAIN difference is 1794 has far better digital filter built in.
There are two different things in your post:
first, I think Kevin suggested 5k at the transformer secondary for the 1798 (3k for 1794 if I do remember) like they do in their passive stage output for the Rakk dac (take a look at the K & K website for the connections).
about my setup, nothing else has to be done on the adaptor board other than you see on the picture and explained in an earlier post. I ordered first an adaptor 1798 board and stripped all the unwanted parts to make the job easy.
Now for IV conversion I prefer for the moment (sonic taste) to load the LL1674 (and that was the same for UTC A20) at the primary. One 220R at each transformer input all wired to the ground. That said, maybe I will try later to load the secondary with different types of resistor.
Correct
If I understood correctly, with the jumper wires in place, it doesn't make any difference if the trafos are connected to R+ R- L+ L- or pins 19/20/23/24. Am I correct?
I should be receiving my board any day now so I'll be able to examine it closer up.
Thanks/Merci
You're right. I put jumpers on adaptor pins because I wanted to have DAC outputs on the main board (my trafos are connected there). But you can just wire the transformers on R+ R- L+ L- .
4398 or 43122
Is it worth the extra money to get this board with the CS43122 instead of the CS4398? I know the 4398 sounds great with no buffers, any problems with running the CS43122 direct out with caps or transformers?
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2010 UP-SAMPLING 24bit/192Hz DAC DA CONVERTER W/USB KIT - eBay (item 130414287425 end time Aug-24-10 22:56:52 PDT)
Is it worth the extra money to get this board with the CS43122 instead of the CS4398? I know the 4398 sounds great with no buffers, any problems with running the CS43122 direct out with caps or transformers?
.
2010 UP-SAMPLING 24bit/192Hz DAC DA CONVERTER W/USB KIT - eBay (item 130414287425 end time Aug-24-10 22:56:52 PDT)
Cs43122
The designer just wrote me back. It seems he prefers the older CS43122 which is interesting because I also like the AK4395 better than the newer AK4396.